Ground loops are parasitic paths in a PCB or an IC that can cause a number of bad effects. These are caused primarily by bad layout, circuit design or interconnections either accidentally or because of lack of experience. In order to avoid ground loops one has to understand what they are. A very brief description is given in a recent article by the techteam at Signal Processing Group Inc., and is available for review at their “engineering pages” in the website located at http://www.signalpro.biz.